Which role does the organic matter play in the soil?

1. Improving water infiltration of the soil.
2. Accelerating break down of organic matter.
3. Reserving nutrients thus providing soil fertility.
4. Converting nitrogen into nitrates.
5. Providing a room for organic material such as nylons.

(viii)   "Organic matter is among the components of soil." Which role does it play?

A    Improving water infiltration of the soil.

B    Accelerating break down of organic matter.

C     Reserving nutrients thus providing soil fertility.

D     Converting of nitrogen into nitrates.

E     Providing a room for organic material such as nylons.

14. Describe six ways that can be adopted by the farmers to maintain soil fertility in Tanzania.

 List two advantages of liming.

       ( State two roles of climate in the soil formation.

 Distinguish manures from fertilizers. Give an example in each case.

In Tanzania, soil conservation is very important for Industrial Materials production. Explain six methods that are used to manage loss of plant nutrients from the soil.

 Define the following terms:

1. Soil.
2. Leaching.
3. Denitrification.

Give the meaning of the following terms.

1. Soil Ph

2. Liming.

 (i) List four effects of excessive nitrogen to plants.

 (ii) State two ways through which soil nitrogen can be lost.

 (ii) Explain four factors affecting soil erosion.

(i)  Soil structure.

(ii)  Acidic soil.

(iii) Liming.

(i) What are the natural causes of soil acidity?

(ii) What cations prevail in acidic soils? (2 marks)

(i) On treatment with calcium hydroxide the soil pH was raised from 5 to 7.

What can you say about the properties of calcium hydroxide?

(ii) What effects can the alkalinity of a soil have on the availability of nutrients?

(iii) Is it sensible to add lime to a field which has received an application of

ammonium sulphate fertilizer? Explain. (5 marks)

 Which reference to pH, solubility and any other factors, list the main properties of the following fertilizers used in our country:

(i) Ammonium sulphate

(ii) Super phosphate

 (iii) Urea (3 marks)

SECTION C (  15 Marks)

Answer one (1) question from this section.

13.    By giving six points, explain how to maintain soil fertility of a particular area.(15 marks)